The Role of Stress Modifier Biostimulants on Adaptive Strategy of Oregano Plant for Increasing Productivity under Water Shortage

Reza Abdali; Amir Rahimi; Sina Siavash Moghaddam; Saeid Heydarzadeh; Carmen Arena; Ermenegilda Vitale; Mohammad Zamanian

doi:10.3390/plants12244117

The Role of Stress Modifier Biostimulants on Adaptive Strategy of Oregano Plant for Increasing Productivity under Water Shortage

Plants (Basel). 2023 Dec 9;12(24):4117. doi: 10.3390/plants12244117.

Authors

Reza Abdali¹, Amir Rahimi¹, Sina Siavash Moghaddam¹, Saeid Heydarzadeh^{1

2}, Carmen Arena^{3

4}, Ermenegilda Vitale³, Mohammad Zamanian⁵

Affiliations

¹ Department of Plant Production and Genetics, Faculty of Agriculture and Natural Resources, Urmia University, Urmia P.O. Box 165-57153, Iran.
² Department of Plant Production and Genetics, Faculty of Agriculture and Natural Resources, University of Mohaghegh Ardabili, Ardabil P.O. Box 179, Iran.
³ Department of Biology, University of Naples Federico II, 80126 Napoli, Italy.
⁴ NBFC-National Biodiversity Future Center, 90133 Palermo, Italy.
⁵ Seed and Plant Improvement Institute, Agricultural Research, Education and Extension Organization (AREEO), Karaj P.O. Box 31585-4114, Iran.

Abstract

To investigate the influence of stress modulators on the adaptive physiological responses and biomass traits of oregano under water stress conditions, a two-year (2018 and 2019) randomized complete block-designed factorial research was performed. In this study, oregano plants were treated with five stress modulators levels (CHN: chitosan, AMA: amino acids, SEW: seaweed, ASA: ascorbic acid, SAA: salicylic acid, and CON: control) at three levels of irrigation regimes (Irr40 (40), Irr60 (60) and Irr75 (75) % field capacity). The effects of water shortage and biostimulant application were evaluated on total dry weight (TDW), relative water content (RWC), essential oil production, chlorophyll, nutrient (N, K, and P), proline, total soluble sugar, polyphenol and flavonoid content, and activity of antioxidant enzymes. The result showed that under optimal irrigation conditions, oregano plants sprayed with CHN exhibited the highest dry weight (141.23 g m^-2) as a morphological trait, the highest relative water content (79.34%), the most consistent concentrations of nitrogen, phosphorus and potassium (3.14, 0.39, and 1.69%, respectively), chlorophylls a and b (3.02 and 1.95 mg g^-1 FW, respectively), and total phenols and total flavonoids (30.72 and 3.17 mg g^-1 DW, respectively). The water deficit increased the proline content, with the greatest amount (4.17 μg g^-1 FW) observed in control plants. Moreover, under moisture shortage stress conditions, the application of CHN and SEW increased the soluble sugar (27.26 μmol g^-1 FW) and essential oil yield (1.80%) production, the catalase, ascorbate peroxidase, and superoxide dismutase activities (3.17, 1.18, and 63.89 μmol min^-1 g^-1 FW, respectively) compared to control plants. In summary, the study demonstrated that oregano plants respond positively to stress modulator treatments when subjected to moisture shortage stress, especially when treated with chitosan. The results offer promising insights for developing sustainable adaptative strategies aimed at enhancing the oregano's tolerance to water shortage, ultimately improving its productivity and biochemical traits.

Keywords: antioxidant; chitosan; optimal irrigation; seaweed; sustainable agriculture.

Grants and funding

This research received no external funding.